This invention relates to optical switches, and in particular to a fiber optic switch using X-Y scanning.
Optical switches are useful for a variety of applications, including fiber optic communications. In one design approach, optomechanical components are used to direct light from a desired optical input to a desired optical output. Conventional optomechanical switches include switches employing moving prisms, and switches employing moving fibers. While optomechanical switches can be relatively easy to manufacture, conventional optomechanical switches can suffer from limited switching speeds, reliability problems, undesirably high insertion losses, and interchannel crosstalk.
The present invention provides an optical switch including an optical input for receiving a light beam; a rotatable-mirror x-y scanner optically coupled to the optical input, for selectively directing the light beam to one of a plurality of output paths; and a two-dimensional array of optical outputs capable of optical communication with the x-y scanner and aligned over an output surface, each of the optical outputs being aligned with one of the output paths so as to receive the light beam when directed by the x-y scanner onto the corresponding output path.
In the preferred embodiment, each optical input and output of the switch comprises an optical fiber collimator. The x-y scanner comprises a first mirror optically connected to the input collimator, for receiving the light beam from the input collimator; a first galvanometer coupled to the first mirror, for rotating the first mirror around a first axis so as to position the first mirror alternatively to any one of a plurality of first mirror positions; a second mirror optically connected to the first mirror, for receiving the light beam from the first mirror; and a second galvanometer coupled to the second mirror, for rotating the second mirror about a second axis perpendicular to the first axis, so as to position the second mirror alternatively to any one of a plurality of second mirror positions. Each of the output collimators is optically coupled to the second mirror, and is aligned with a ray corresponding to one of the first mirror positions and one of the second mirror positions. A light beam received at the switch input is directed to any one of the output collimators by rotating the first mirror and the second mirror to predetermined mirror positions corresponding to the selected output collimator.
The switch allows using relatively light moving parts, such as mirrors, which allow improved switching speeds. The galvanometer motors are capable of fast and precise positioning of the mirrors. Appropriate alignment and positioning of the optical input(s) and output(s) allow relatively low and uniform insertion losses.